Electric signal system



0th 14, 1930 c, c, FARMER ET AL 1,778,108-

ELECTRIC SIGNAL SYSTEM Filed March -25 1927 X a I P) a v mvsrrrons CLYDE RM R THOMAS l-LTHOMAS 1 ATTORNEY I Patented Oct. 14, 1930 UNITED STATES PATENT OFFICE CLYDE C. FARMER,'OF PITTSBURGH, AND THOMAS H. THOMAS, 013 EDGEWOOD, PENN- j SYLVANIA, ASSIGNORS TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF WIL- 'MERDING, PENNSYLVANIA, A CORPORATION OF ?ENNSYLVANIA ELECTRIC SIGNAL SYSTEM Application filedMareh 25, 1927. Serial No. 178,305.

This invention relates to signal systems,

andmore particularly: to an electric slgnal ling" system adapted for use on railway trains.

,The' principal object of our invention is to provide an electric signal system employing only a single train wire and in which a source of current is not required on the locomotive or head car In the accompanying drawing; Fig; 1 is a diagrammatic view of an electric signal system embodying our invention; Fig. 2 a

section on the line 22 of Figl l; and-Fig. 3' a section on the line 33 of Fig'l.

Accordlng to a preferred form of our invention, there is provided on each car of the 7 train a buzzer device comprisingian electromagnet 1 having two magnet windings or coils 2. and 3 and a pivotedarmature 4, movable in one direct on by aspr'ing 5, when the magnet is deenergized and in the opposite directlon when the magnet is energized. One

terminal of each'coil 2and 3 is connected to a single train wire 6, and the other te'rmi nal of coil 2is connectedfto a wire 7 which leads to a contact 8 controlled by a plug switch device comprising a casing 9 having a tapered bore adapted to receive a removable switch plug 10. The switch plug 10 carries contactsll and 12. I

A' branch wire 13 leads from'wire 7 and switch device comprisi'nga casing 15 containing a slidi'ng contact member 16. Said contact member 16 is provided withanoperating stem 17 adapted to beoperatedbya lever 18 having two operating arms 19 and 20, each adapted to. be connected to an operating cord and having two fulcrum pins 21 V and 22, so disposed that'when the arm is operated, the lever 18 turns about'the fulcrumpin 22to operate the stem 17 and when the arm 19 is operated, the lever 18 turns about the 21 to operate the stem 17 i The contact member 16 is provided wlth contacts 23 and 24 and is normally mainby the action of a coil spring 25. When thetained in the position shown in the drawing member l6'is moved downwardly a predetermined distance, a yieldingstop member 26 is engaged, said stop member being subect tothe pressure of a coil spring 27. In

order to prevent rotative movement of the contact member 16, said member is provided with a spline 28 whichengages in a groove cut in guide bushing 29 having screw-threaded engagement in the casing 15. The switch plug 10 may also be provided with a spline 30 adapted to engage in a groove in the cas- 9, so as to ensure that the plug will be inserted in the proper position.

The contact 24 controls circuit wires connected to the contact 14, to contact 31 which is connected to wire 32 leading to one terminal of magnetcoil 3, and to contact 33 which is connected to wire 34 leading to the position terminal of a battery 35, or other source of electric current. I p The contact 23 controls circuit wires connected to contacts 36 and 37, the contact 36 being connected to a wire 38, leading to the negative terminal of the battery 35, and the contact 37 being connected to a wire 39 which is connected to ground at 40' and which also leads to a contact 41 controlled by the contact'12 of the switch plug 10.

The wire 34 is also connected to a contact 42 controlled by the contact llof the switch plug 10, and the negative terminal of the battery35 is connected by wire 43 to a contact 44 controlled by contact 12 of the plug switch 1O.

On the locomotive, there is provided a SWl'EClldeVlCB comprising a casing 45 in which is slidably mounted a contact member '46having a contact 47 and normally main tained in the position shown in the drawing by theaction of a coil spring 48.

The train wire 6 is connected with two buzzers 49. and-5O in parallel, of the well known type, which operate by making and breaking the electric circuit. The buzzer 49 is connectedthrou'gh wire 51 with a contact 52 and the buzzer through wire 53 with a contact 54.

In normal position of the switch member 46,

the contact 47 connects contact 52 with a contact '55 having a connection with a wire 56 leading to ground at 57 and when the member 46 is depressed, the contact 47 connectsconnot respond to'current flowing through the winding 2jbut will respond to current flowing through the winding V 'lhe buzzer 50 is so constructed thatit will respond to current flow through either the winding 2 or 3.

, There are dii'lerent ways, wellknown iii'the art, for varying the responsiveness of the buzzers 4:9 and 50, such as, for example, by

varying the resistance of the buzzer windings,

varying the number of turns of the windings, by, Trying the magnet air gap between the in giiet poles and the armature, or the pull of the usual spring which acts on the magnet armature, or by varying'two-or more of the above adjustments.

' The buzzer 4L9 out-lie locomotive and the coil 2 of each electrounagnetl on each vehi cle oi' the train are ofsuiiiciently high resist ance, so that even if all the plugs 10 on the train are inserted, there will. not be enough current flowing tl'irough. the buzzer lilto cause same to operate.

in operation, pluglO isinserted in the casing 9b a trainrnan on each vehicle of the trainat which it is desired to receive signals 7 originated by the engineinan.

If the engineinan desires to signal, he depresses the switch member 46, so that a circuit is closed from he ground ,57'througli the. buzzer 5O to the train wire 6', while the circuit through'the buzzer 49 is opened.

on cars in which the plug lO is'iiiserted, a

. circuit will then becoinpleted from the train whee through magnet coil 2, wire 7, Contact 11 ot'lth'eplug switch, WlI'Q 3%, battery 35, M wire 43, contact 12 otthe switch 'plug'lO, and

"wire 39 to ground'atflO. r

The buzzer on the locoi'notive'isthus caused to operate and n operation, it makes breaks thecircuit, so that the circuit of 'viiieinan he causes thelever '18 to bee erated the train the jcoilf2 i's likewise made and-brokenand h buzzer and thus a signal is given oncars in which the plug 10is-ins'erte'd.

therebyth; armature 41- is caused to operate as The buzzer Oalso operatesas a 'signzalto N the enginenian' that the apparatus is working piope rly and that a signal isbeing made on the cars ofthe train. r y Vlhen a trainman desires to. s gnal the en- "so as to depress the stem 17, until the contact member lfi-eiii a 'es'the etc 26. Thiscompletesa circuit from ground 40 to the train through contact 23, wire 38, battery 35,

On thelocoinotive, the switch member 46 being in normal position, as shown in the the operating position.

J 23, wire 38, battery tters Patent, is v e s, contact 2 wire 32, and magnet coil 1 drawing, the train Wire is connected to ground through buzzer 19, wire 51, contact 4:7, and wire 56 to ground at 57.

'ihe magnet con 3 is or low resistance as compared with magnet coil2 and such that suilicient current will flow through the buzzer 49 to cause same to operate and thus signal the enginen aii. I 'IllQbLlZZQI i9 being in ci cuit with the coil 3,;Will, by itsoperation, cause the circuit through the coil3 to be made and broken and thereby the armature l will be caused to vibrate.

It will be noted that a ti'ai iman may signal 7 the engineman as above described, regardless of whether or not the plug 10 is inserted in li a'fter traiinnan has signalled the engineman, the trainman wishes the engineinan to answer at the point from which he signalled the engineinan, the trainman will further depi'essthe switch ii'iembe 16, so as to move the :yieldiiig stop 26 downwardly.

A circuit to the train wireb is thencompletedfrom the ground {i0 through contact 35, Wire 34, contact 24, wire 13, wire 7, and through theinagnet coil 2, to the train wire 6. On the locomotive,

'the'circuit is completed through the buzzer 4:9 and the switch member 46 to the ground,

and since the buzzer 49 will not operate with i the magnet coil 2 in circuit, and sincethe circuitot the 00113 is now open, the armature a" Willcease buzzing when the contactswitch member 16 is fully depressed, and thus will 7 indicate to thetrainman that he has properly depressed the switch member 16 to 'iierinit the enginemau to signaljbac'k.

It, with the switch member 16 fully" depressed, the engineman depresses the switch member 46, a circuit Wlll becompleted on the locomotive through 1 the" buzzer 50 and through the magnet coil 2 on the car, and the I circuit through the coil tZand the battery 35 i being closed in the fully depressed position oi' the switch member 16, as;above"described":-

the operation or the buzzer50 on the 'locoinotive makes and breaks the circuit through the 5 coil 2 andfthus causes the armature 4: to act as Li a, buzzer and as a signal irom the-engineman Ito the trainman.

A rectifier 6001' other means for permitting flow oi current onlyin one direction may be interposed 111 the w1re34, so that should 1. In an electric signal system, a train signal circuit, two signal devi'ces'ata first statlon'connected'in'said circuit, a signal de its " the voltage oi the battery 35 on one car be in excess of that on another car, there will be" vice at a second station having two energizlng co1ls connected in said circuit, one of the signal devices at the first station being re- .sponsive to current flow through one coil but not to current flow through the other coil and the other signal device at the first station being responsive to current flow through said other coil, means at the first station for clos- 1 ing the circuit through either one of said signal devices at the first station, and means at the second station for closing the circuit through either one of said coils.

2. In an electric signal system, a train signal circuit, two signal devices at a first station connected in-said circuit, a signal device at a second station having two energizing coils connected in said circuit, one of the sig nal .devices at the first station being responsive to current flow through one coil but not to current flow through the other coil and the other'signal device at the first station being responsive to current flow through said other coil, a manually operable switch device at the first station for closing the circuit to one of the signal devices at the first station in one position and for closing the circuit to the other signal device at the first station in another position, and a manually operable switch device at the second station for closing the circuit of one coil in one position and for closing the circuit of the other COll in another position.

3. An electric signal system for signaling from one station to another station including a train signal circuit, a signal device at a first station having two energizing coils of different resistances connected in said cir- 'cuit, means at the first station for energizing station having two energizing coils connected in said circuit and operative by the making and breakinx o1 the circuit through one of said coils, means at the first station for supplying current through either one or the other of said coils, two automatic circuit make and break devices at second station connected to said train wire, one of said signal devices at the second station being responsive to current flowing through one coil but not to current flowing through the other coil,"and

means at thesecond station for closing the circuit through either one or the other of said automatic circuit make break devices at the second station. 7

5.- In an electric signal system, the combination with a train signal circuit, of a signal device in said circuit on one car of a train for making a signal by the making and breaking of the circuit and having two energizing coils one of greater resistance than the other, a manually operated switch for locally closing the circuit through one coil, a manually operated switch for locally closing the circuit through the other coil, two automatic circuit make and break devices in said circuit on another vehicle of the train, so related that one will operate when in series with the high resistance coil and the other will not, and a manually operated switch for locally closing the circuit through either one of said make and break devices.

6. In an electric signal system, the combination with a train signal circuit, of a signal device in said circuit on one car of a train for making a signal by the making and breaking of the circuit and having two energizing coils, one of greater resistance than the other, a inanually'operated switch for locally closing the circuit through one coil. a manually operated switch for locally closing the circuit through the other coil, two automatic circuit make and break devices in said circuit on another vehicle of the train, so related that one will operate when in series with the high resistance coil and the other will not, and a manually operated switch for locally closing the circuit through either one of said make and break devices and adapted to normally close the circuit through. the make and break device which is not responsive to current flowing through the high resistance coil.

lUQ

I In testimony whereof we have hereunto set 

